Base and based electric device



Feb. 5, 1935.- E. c. BRUECKMANN 1,989,786

BASE AND BASED ELECTRIC DEVICE Filed July 12, 1933 Patented Feb. 5. 1935 UNITED STATES BASE AND BASED ELECTRIC DEVICE Earl C. Brueckmann, Bloomfield, N. 1.. adgnor to Westinghouse Lamp Company, a corporation Pennsylvania Application July 1:, 1m. Serial No. scam is Claims. (01. 110-122) This invention relates to based electric devices and luminous discharge devices and more particularly to devices of this character employing analkalimetalsuchassodlumorthelikewith l or without a rare gas as the light producing medium therein. In its more specific aspect the invention is directed to an improved sodium vapor lamp construction which may be readily manufactured and which has a number of other ad- 10 vantages over prior art devices.

In the patent application of John W. Mai-den filed April 29, 1933 and bearing Serial No. 668,506 there is described a sodium vapor lamp. Said application is assigned to the same assignee as the present invention. The lamp comprises a dielectric envelope having a thermionic cathode and a plurality of anodes therein. Also contained within said envelope is an appreciable quantity of an alkali metal such as sodium and a small quantity of a rare gas such as neon, argon or the like. Surrounding said envelope is a double-wall evacuated chamber. Between the envelope and the inner wall of said chamber at the lower portions thereof is a collar or packing for sealing the air space between said envelope and chamber.

It has been recognized that the equilibrium vapor pressure of the sodium within the envelope is dependent upon the temperature of the sodium at the coolest portion of the envelope. That is to say if the temperature throughout the major portion of the envelope is 300 C. and the coolest portion of said envelope is 250 C., condensation of the sodium vapor takes place and the vapor pressure of the sodium is equal to the vapor pressure of sodium at 250 C.

Since one of the prerequisites of eillcient sodium vapor lamp operation is that the temperature of the sodium at the coolest portion of the envelope shall be at least a certain magnitude, envelope cooling has been an important consideration in my sodium vapor lamp design and especially in the design of the base therefor.

Accordingly I have provided an alkali vapor lamp, such as a sodium vapor lamp, having a novel base associated therewith. The construction of the base and the manner in which it is connected with the envelope'of the lamp providesa simple and eiilcient structure whereby a minimum of envelope cooling may take place. 5 In addition I obtain a higher lumen output by basing my lamps in the manner hereinafter described In its simplest aspect the invention comprises a novel based electric device, such as a sodium 55 vapor lamp. having an envelope and a base, with but a small portion of the surface thereof in conwith said envelope. The envelope has electherein and lead wires for said electrodes in said envelope. These lead wires are connected to contact pins. This mode of connection is simple and maintains the base in position to eliminate the use of basing cement.

An object of my invention is to provide a novel sodium or the like vapor lamp construction.

Another object of my invention is to provide 5 a new type of base for an electric device.

Another object of my invention is to provide an improved construction of a sodium or the like vapor lamp and base. 7

Another object of my invention is to provide a simple and inexpensively based electric device.

Another object of my invention is to provide a novel based sodium or the like vapor lamp having electrode leads secured to a base in a novel manner so that the electrical characteristics of the lamp shall be improved.

Other objects and advantages of my invention will be readily apparent from the following description and drawing wherein,

Figure 1 is a longitudinal cross sectional view with some of the parts in eleva'tion,of a lamp embodying my invention;

Figure 2 is a top plan view of my novel base;

Figure 3 is a perspective view of the top portion of the base embodying my invention.

Figure 4 is a cross-section view of a detail of a modified form of a base embodying my invention.

As shown in Figure l, the lamp comprises a sodium resistant glass bulb 10 having a reentrant stem 11. The reentrant stem 11 has a press 12 in which are sealed a plurality of spaced lead-in conductors 13, 14, 15 and 16. The lead-in and supporting conductors l4 and 15 are connected respectively to the free ends of a cathode 19. The cathode 19 may comprise a coiled tungsten filament which serves as a heater element and support for a coiled filament of nickel wound therearound and having a thermionically active coating, such as an admixture of alkali earth carbonates. as for example, calcium, barium and strontium carbonates thereon. The cathode 19 serves as a heat supply means and as an electron source.

The lead-in and supporting conductors 13 and 16 have their upper ends respectively secured by welding to a pair of spaced supporting conductors 20 and 21. These conductors 20 and 21 are spaced fromand are substantially parallel to each other. The lower ends of said conductors 20 and 21 are located below the press 12 and are diametrically disposed on opposite sides of the press around which is located a nickel sheet or shield 22 for protecting the seal and press from t.

Concentric with the stem 11 and located below thepress12areapluralityofcircularbands23 and 24 of molybdenum orthe likeclectrieallysscuredtothe lower ends ofthe respective conductors20and2l. Thecircularbands23and24are spacedfromtheshield22,arespacedfromeach other and serve as anodes. At the upper ends respectively of the conductors 20 and 21 are secured a pair. of spaced circular bands 25 and 26 which are concentric with each other. The ele-' ments 25 and 26 of the same composition and size as the bands 23 and 24 also serve as anodes. At that portion of the conductors 20 and 21 opposite the cathode 19 are secured by welding a pair bf short stud conductors 27 and 28 having their free ends adjacent and properly spaced from the cathode 19. These conductors 27 and 28 serve as starting anodes and cooperate with the cathode 19 to initiate a discharge. An insulator 29 is connected to the upper anodes to maintain them in proper spaced relationship.

Within the envelope is contained a rare gas, such as neon or argon, at a pressure of about V2 to 4 mm. of mercury. The rare gas assists in making possible the initiationof the discharge.

Also contained within said envelope is a suitable alkali metal such as sodium. potassium, caesium or rubidium. These elements may be introduced into the envelope by electrolytic or other means. For my purpose I prefer to employ electrolytic sodium. The supporting conductors have sleeves 30 of alundum or the like covering the same to eliminate ho'tfspots thereon and sputtering therefrom.

Surrounding the lower end of the envelope of bulb 10 is a base. According to my invention I provide a novel base 31 so that the requisite temperature of the sodium vapor during lamp'operation may be maintained. The base comprises a tubular sleeve or collar 32 composed of a rigid insulating material, such as, isolantite, transparent glass or the like.

- The thickness of the collar is small as compared to the diameter of the collar and measures about one tenth of said diameter. 30 that the collar 32 shall not be a good conducting path for the heat'generated in said envelope 10 during discharge, the collar has three upwardly extending lugs 33 ofisolantite, transparent glass or the like at the upper end thereof and spaced about 120 apart. The lugs 33 are of substantial height. As shown in Figure 1 the collar 32 surrounds the lower portion of the bulb and has the major portion thereof spaced therefrom. The lugs rest against and are in firm contact with the bulb. If desired-Imay have a plurality of depressions in the bulb to accommodate these lugs, each of whose circumferential length is about onefortieth the circumference of the collar. The width of each depression is about the same and preferably just slightly greater than the width of each lug 33.

When I provide very slight depressions in the glass the upper ends of the lugs may be rounded to fit snugly therein. The lugs 33 may be of triangular cross sectional contour and when the collar is mounted there is a simple line contact 7 between each of the lugs and the bulb.

The depth of the lugs is appreciable and may be of such a magnitude that the lower extremities thereof shall be below the lower extremity of the envelope. with this construction the base does not intercept any appreciable portion of the light rays that travel in a direction other than that parallel to the longitudinal axis of the envelope. Besides having this advantage, the heat conductingpath of the base is reduced to a minimum because of the'relatively small area of contact between the bulb and the base.

The collar 32 has a recess 32' along the lower portion thereof in which a cup as composed of bakelite or the like may fit. The upper end of the cup 34, bears against the shoulder 33' of said collar 32 which shoulder definesthe upper limit of said recess. The'cup 34 has a plurality of hollow conducting pins 35, four in number. firmly secured thereto.

Instead of employing a base comprising a collar 32 and cup 34, the base may be a unitary single element comprising a cup composed entirely of a heat resisting material, such as isolantite, transparent glass or the like and having lugs 33 as hereinbefore described.

As far as I am aware I am the first to mount the base as shown in Figure 1. Each ofthe leadin conductors as illustrated comprises an inner lead portion, a press portion and an outer lead portion. The outer lead portion of each of said lead-in conductors may be a multi-strand element. The outer lead portions are respectively inserted through the hollow conducting brass pins 35 secured to the base. In order that any cementing between the base and envelope may be eliminated, tension is applied to the outerlead portions while the base is maintained stationary and against said envelope. with the tensile force applied to said lead portions. the separate outer leads are secured to their corresponding leads by a simple soldering operation. The base having its lugs 33 located in depressions of the envelope does not allow the base to turn around the envelope, and theouter leads being under tension and secured to the hollow pins allow no movement ,of

rically opposed, stub'pin thereon. One end of each pin has diametrically opposed slots extend-, ing from the one limit thereof to about the mid length thereof. The pins of the bushing fit in said slots and the outer end of the bushing is screw threaded. 1 A nut may be employed and cooperates with said bushing to apply the proper tensile force to said lead when the nut is tightened against the pin of the base. A small coil spring may be located in a small recess in said bushing and bears against the shoulder of said recess and said nut.

To further provide for maintaining the requisite sodium temperature, I provide a double walled vacuum chamber 40 surrounding said lamp. The open end of said cha r surrounds said base 31.

A packing 41 of ins ating material is located in stantial air circulation between the outer atmosphere and the air contained in the space defined by said envelope 10, said base and the inner wall of said chamber.

My invention is susceptible to numerous modifications and is to be limited only by the prior art.

What is claimed is: e

1. An electric device comprising an envelope, an anode, a cathode and an alkali metal within said envelope, a base surrounding a portion of said envelope, said base having a plurality of spaced lugs bearing against said envelope, the remainder of said base being out of contact with said envelope, the space between said'envelope and the inner wall of said base being substantially unfilled.

2. An electric device comprising an envelope, an anode, a cathode and an alkali metal within said envelope, a base surrounding a portion 01' said envelope, said base being a hollow cup and having a plurality oi spaced lugs bearing against said envelope, the remainder of said base being out of contact with said envelope, a plurality of leading-in conductors secured to said anode and cathode, said base having conducting pins secured thereto, s: id leading-in conductors being electrically connected to said pins.

3. An electric device comprising an envelope, an anode, a cathode and an alkali metal within said envelope, a base for said envelope said base having a plurality of lugs bearing against said envelope, said envelope having means cooperating with said lugs i or seating said base, the remainder of said base being out of contact with said envelope.

4. An electric device comprising an envelope, an anode, a cathode and an alkali metal within said envelope, said envelope having depressions, a base for said envelope, said base having a plurality of spaced lugs seated in said depressions, the remainder of said base being out of contact with said envelope.

5. An electric device comprising an envelope, an anode, a cathode and an alkali metal within said envelope, a base for said envelope, said base having a plurality oi spaced lugs bearing against said envelope, the remainder of said base being out of contact with said envelope, an evacuated chamber surrounding said envelope and a portion of said base, an insulating packing material located in the space between said base and the lower portion of said vacuum chamber.

6. An electric device comprising an envelope, an anode, a cathode and an alkali metal within said envelope, a transparent base for said envelope, said base having a plurality of spaced lugs bearing against said envelope, the remainder of said base being out of contact with said envelope.

'7. An electric device including an envelope, a

plurality oi leading-in conductors having outer lead portions, a base surrounding a portion of said envelope and having conducting pins secured thereto, said leading-in conductors cooperating withsaidpinstomaintainsaidbaseagainstsaid envelope. Y

8; An electric device comprising an envelope having a press, a plurality of leading-in conductors sealed in said press, a base surroimding said envelope, a plurality of spaced pins secured to said base, the outer portions of said leading-in conductors cooperating with said pins to maintain said base in position wholly through the force" exerted on said base by saidconductors.

I having a press, a plurality of leading-in conductors sealed in said press, a base surrounding said envelope, a plurality of spaced hollow pins secured to said base the outer portions of said leading in conductors extending through said pins and cooperating therewith to maintain said base in position wholly through the force exerted on said base by said conductors.

11. An electric device including an envelope having a press, a plurality of leading-in conductors sealed in said press, a base for said envelope, a plurality of spaced hollow pins carried by said base, the outer portions of said leadingin conductors extending in said hollow pins and secured thereto, said leading-in conductors cooperating with said base to maintain said base in position wholly through the force exerted on said base by said conductors.

12. An electric device including an envelope having a press, a plurality of leading-in conductors sealed in said press, a base for said envelope, means on said base cooperating with said envelope tor preventing said base from turning about said envelope, a plurality of spaced pins carried by said base, the outer portions of said leading in conductors cooperating with said pins to maintain said base in position wholly through the iorce exerted on said base by said conductors.

13. An electric device including an envelope having a press, a plurality of leading-in conductors sealed in said press, a base for said envelope, said base having a plurality of spaced lugs, said envelope having depressions, said lugs being located in said depressions, a plurality of spaced pins carried by said base, the outer portions of said leading-in conductors secured to said pins for maintaining said base in position wholly through the force exerted on said base by said conductors.

14. An electric device comprising an envelope, an anode and a cathode within said envelope, a plurality oi leading-in conductors for said electrodes, a base for said envelope, said base having a plurality of spaced pins secured to said base, the outer portions of said leading in cnductors secured to said base for maintaining said base in position wholly through the force exerted on said base by said conductors.

15. An electric device including an envelope, a base for said envelope, a conductor secured to said envelope and extending in said base, said conductor being secured to said base and cooperating therewith to maintain said base in position wholly through the force exerted on said base by said conductor.

16. An electric device comprising an envelo having a press, means sealed in said press, a base for said envelope, a d means extending through said base and cooperating therewith to'maintain said base in position wholly through the force exerted on said base by said means.

-\ 17. An electric device comprising an envelope,

an anode, a cathode and an alkali metal within said envelope, said envelope having a press, a base for said envelope, a plurality of, spaced pins secured to said base, a plurality of leading-in conductors sealed in said press, the outer portions of said leading-in conductors cooperating with said pins to maintain said base in position wholly through the force exerted on said base by said conductors.

18. An electric device including an envelope, iplurality of leading-in conductors having outer lead portions, a base surrounding a portion of said envelope and having conducting pins secured thereto, resilient means cooperating with said pins and said conductors to maintain said base against said envelope.

EARL C. BRUECKMANN. 

